Some prior arts, such as U.S. Pat. No. 6,375,005, U.S. Pat. No. 6,409,015 and U.S. Pat. No. 6,464,840 disclose structures about exhibition frames.
In these prior arts, when a ratchet spanner restores, a hexagonal seat will rotate with the ratchet spanner due to the defect in the design of the seat and the suspending plate. Thereby the ratchet spanner loses the mechanism of idle rotation in restoring. However this is not beneficial in test. Thus in test, the user can only test the spanner in a predetermined direction. The user cannot know the smoothness of the spanner as the spanner idly rotates. Thereby the prior art is not an idle design.